EPEL Packaging

This page contains guidelines which are no longer relevant to Fedora, but still apply to EPEL packages. These guidelines are designed to avoid conflict with the larger Fedora Packaging Guidelines, but should any conflicts occur, these guidelines should take precedence (on EPEL packages).

As a reminder, these guidelines only apply to EPEL packages, not to Fedora packages.

Limited Arch Packages

Red Hat Enterprise Linux does not ship the same packages for all of its available architectures. If your EPEL package requires or buildrequires a package that is not available on an architecture, it is allowed to use ExcludeArch to match the architectures of it’s dependencies. If the dependencies are present in all architectures but you still have a build failure, you must follow the Fedora Architecture Build Failures guidelines.

For EPEL-7, it is allowed for EPEL to ship a package which was the same as what was in RHEL but built with changes listed below.

  1. Make sure the package is not shipped for all architectures. The valid architectures are:

    • EPEL7: ppc64le, x86_64.

    • EPEL8: Because we have had problems with these packages causing either build, compose, or user problems, we are not allowing this for EPEL8.

  2. Make sure the package meets the Fedora licensing and distribution rules. Nothing non-free or under an unacceptable license.

  3. Notify the epel-devel list of your intention to add this package.

  4. Change the release of the package to have a leading 0. EXAMPLE: RHEL has foobar-1.0-1, you change it to foobar-1.0-0.1 for EPEL.

  5. Add a Changelog entry that the package was added to EPEL and has a 0 leading version to keep it older than RHEL.

  6. Request the branch you need (epel7) using fedpkg request-branch.

  7. Import and build your package, submit as update.

  8. Watch the RHEL version of the package. When it updates, you should update the EPEL version too. You should never update other than that.

Do not add ExclusiveArch tags, this will break building on the other architectures!

EPEL 8

Scriptlets

Fedora has been moving towards the use of file triggers and away from requiring that packagers cut and paste scriptlets into loads of packages. At the time of this writing, we are trying to backport all of these to EPEL8, so that fedora packages are easily able to build on EPEL8 without any changes. When EPEL 8 becomes old enough, that these backports are not feasible and/or wanted, we will list them here.

EPEL 7

Rich Dependencies

RHEL 7’s rpm and yum versions do not support rich or boolean dependencies, so these are not allowed in EPEL 7.

Scriptlets

Fedora has been moving towards the use of file triggers and away from requiring that packagers cut and paste scriptlets into loads of packages. These scriptlets would still be needed for EPEL, and as scriptlets are no longer needed in any Fedora release, they’re moved here.

Shared Libraries

On EPEL 7 and older, ldconfig MUST be called properly in order to regenerate the dynamic linker’s cache. If the package or subpackage has no existing %post or %postun scriptlets, simply include the %ldconfig_scriptlets macro on its own line before the %files list.

[...]
%install
# Install the program

%ldconfig_scriptlets libs

%files libs
%license GPL
[...]

Using the %ldconfig_scriptlets macro will automatically generate a dependency on ldconfig where necessary. The macro will do nothing at all in Fedora.

If the package or subpackage already has existing %post or %postun scriptlet, then use of %ldconfig_scriptlets will cause an error. You can use %ldconfig_post or %ldconfig_postun individually to generate a scriptlet which doesn’t already conflict.

Within an existing %post or %postun scriptlet, use %{?ldconfig} on its own line to call ldconfig on those releases which need it. This will do nothing when not needed. When calling ldconfig in this way, you MUST also have the proper dependency on /sbin/ldconfig: Requires(post): /sbin/ldconfig and/or Requires(postun): /sbin/ldconfig as appropriate. (This will generate an unnecessary dependency on releases which do not strictly need it, but this does no harm.)

GSettings Schema

GSettings is the configuration system used by the GNOME 3 desktop. It replaces the older GConf system, which was used in GNOME 2. GSettings has pluggable backends, the 'native' one for GNOME is using DConf to store settings. The GSettings API and utilities are part of the glib2 package.

Programs which use GSettings install schema information including default values in the directory %{_datadir}/glib-2.0/schemas. Schema files are xml files with the extension .gschema.xml. At runtime, GSettings uses the schemas in a compiled binary (but arch-neutral) form, which is created by running the glib-compile-schemas utility. /usr/bin/glib-compile-schemas must be run whenever the set of installed schemas changes.

%postun
if [ $1 -eq 0 ] ; then
    /usr/bin/glib-compile-schemas %{_datadir}/glib-2.0/schemas &> /dev/null || :
fi

%posttrans
    /usr/bin/glib-compile-schemas %{_datadir}/glib-2.0/schemas &> /dev/null || :

gdk-pixbuf loaders

gdk-pixbuf is a library that is part of the gdk-pixbuf2 package. It is for loading images in various formats in GNOME. gdk-pixbuf can be extended by implementing loaders for image formats in loadable modules. These loadable modules have to be installed in %{_libdir}/gdk-pixbuf-2.0/2.10.0/loaders. To avoid opening all modules in that directory unnecessarily, gdk-pixbuf maintains a cache with information about the available modules in the text file %{_libdir}/gdk-pixbuf-2.0/2.10.0/loaders.cache. This cache file needs to be updated when the set of installed modules changes, by calling the /usr/bin/gdk-pixbuf-query-loaders binary. Multilib considerations force us to install the binary in -32 and -64 variants.

The scriptlets to maintain the cache file are:

%postun
    /usr/bin/gdk-pixbuf-query-loaders-%{__isa_bits} --update-cache &> /dev/null || :

%post
if [ $1 -eq 1 ] ; then
    # For upgrades, the cache will be regenerated by the new package's %postun
    /usr/bin/gdk-pixbuf-query-loaders-%{__isa_bits} --update-cache &> /dev/null || :
fi

Note the use of %{__isa_bits}, which is an rpm macro that expands to either 32 or 64, depending on the architecture of the package.

GTK+ modules

The GTK+ toolkit (in the gtk3 package) can be extended by loadable modules which can provide theme engines, input methods, print backends or other functionality. These modules have to be installed in subdirectories of %{_libdir}/gtk-3.0 or %{_libdir}/gtk-3.0/3.0.0. For the input methods, GTK+ maintains a cache in the text file %{_libdir}/gtk-3.0/3.0.0/immodules.cache. This cache file needs to be updated when the set of installed input methods changes, by calling the gtk-query-immodules-3.0 binary. Multilib considerations force us to install the binary in -32 and -64 variants.

The scriptlets to maintain the cache file are:

%postun
/usr/bin/gtk-query-immodules-3.0-%{__isa_bits} --update-cache &> /dev/null || :

%post
if [ $1 -eq 1 ] ; then
    # For upgrades, the cache will be regenerated by the new package's %postun
    /usr/bin/gtk-query-immodules-3.0-%{__isa_bits} --update-cache &> /dev/null || :
fi

The 3.0 in the binary name is there because gtk2 has its own utility for the same purpose, called gtk-query-immodules-2.0. Note the use of %{__isa_bits}, which is an rpm macro that expands to either 32 or 64, depending on the architecture of the package.

GIO modules

GIO is a library that is part of the glib2 package. It is a low-level part of the GNOME stack. GIO can be extended by implementing extension points in loadable modules. These loadable modules have to be installed in %{_libdir}/gio/modules. To avoid opening all modules in that directory unnecessarily, GIO maintains a cache with information about the available modules in the text file giomodule.cache in the same directory. This cache file needs to be updated when the set of installed modules changes, by calling the gio-querymodules binary. Multilib considerations force us to install the binary in -32 and -64 variants.

The scriptlets to maintain the cache file are:

%postun
/usr/bin/gio-querymodules-%{__isa_bits} %{_libdir}/gio/modules &> /dev/null || :

%post
# We run this after every install or upgrade because of a cornercase
# when installing the second architecture of a multilib package
/usr/bin/gio-querymodules-%{__isa_bits} %{_libdir}/gio/modules || :

Note the use of %{__isa_bits}, which is an rpm macro that expands to either 32 or 64, depending on the architecture of the package.

mimeinfo

Use this when a package drops an XML file in %{_datadir}/mime/packages.

%post
/bin/touch --no-create %{_datadir}/mime/packages &>/dev/null || :

%postun
if [ $1 -eq 0 ] ; then
  /usr/bin/update-mime-database %{_datadir}/mime &> /dev/null || :
fi

%posttrans
/usr/bin/update-mime-database %{?fedora:-n} %{_datadir}/mime &> /dev/null || :

Note that similarly to the gtk-update-icon-cache code, these scriptlets should be run only if the user has update-mime-info installed and without a specific Requires: shared-mime-info. If shared-mime-info is not installed, update-mime-database won’t be run when this package is installed. This does not matter because it will be run when the shared-mime-info package is installed.

desktop-database

Use this when a desktop entry has a MimeType key.

%post
/usr/bin/update-desktop-database &> /dev/null || :

%postun
/usr/bin/update-desktop-database &> /dev/null || :

Note: This scriptlet follows the same convention as mimeinfo files and gtk-icon-cache. Namely, the spec file should not Require desktop-file-utils for this. For older releases, one should

Requires(post): desktop-file-utils
Requires(postun): desktop-file-utils

Icon Cache

If an application installs icons into one of the subdirectories in %{_datadir}/icons/ (such as hicolor in the following examples), icon caches must be updated so that the installed icons show up in menus right after package installation. This consists of updating the timestamp of the top-level icon directory where the icons were installed, and running gtk-update-icon-cache. 'touch’ing the top-level dir is done so that environments compatible with the Icon theme specification can refresh their caches, and gtk-update-icon-cache which is additionally required for GNOME also does its work based on the dir timestamp.

Note that no dependencies should be added for this. If gtk-update-icon-cache is not available, there’s nothing that would be needing the cache update, ditto if "touch" is not available, there’s nothing that would benefit from icon cache updates installed yet either. Not adding the dependency on gtk-update-icon-cache (ie. gtk2 >= 2.6.0) or "touch" makes it easier to use the package (or the same specfile) on systems where it’s not available nor needed, such as older distro versions or (very) trimmed down installations, and generally results in less entries in specfiles, rpmdb, and repo metadatas.

%post
/bin/touch --no-create %{_datadir}/icons/hicolor &>/dev/null || :

%postun
if [ $1 -eq 0 ] ; then
    /bin/touch --no-create %{_datadir}/icons/hicolor &>/dev/null
    /usr/bin/gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || :
fi

%posttrans
/usr/bin/gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || :